#define _CRT_SECURE_NO_WARNINGS
#include <iostream>


using namespace std;


class Solution {
public:
    int tribonacci(int n) {
        int dp[40];
        dp[0] = 0;
        dp[1] = dp[2] = 1;

        for (int i = 3; i <= n; ++i)
            dp[i] = dp[i - 3] + dp[i - 2] + dp[i - 1];

        return dp[n];
    }
};

int main()
{

	return 0;
}